The present invention relates to an electronically controllable vehicle braking system for a motor vehicle with a cylinder/piston arrangement providing a brake fluid, which, by actuating a brake pedal, is caused to provide brake fluid acting on the brake of the motor vehicle, with the cylinder/piston arrangement being connectable with a pump arrangement and a pressure accumulator with the pressure accumulator having a housing which comprises a fluid connection for a fluid flowing into and out of the housing as well as a spring arrangement against whose force brake fluid flowing through the fluid connection is acting, characterised in that at least one part of the spring arrangement is formed by at least one part of the housing wall.
The invention also relates to a pressure accumulator, in particular for such an electronically controllable vehicle braking system comprising a housing, a fluid connection for fluid flowing into and out of the housing, as well as a spring arrangement against whose force brake fluid flowing in through the fluid connection is acting.
From the state of the art pressure accumulators are known which are designed as gas piston accumulators, as gas diaphragm accumulators or as gas multilayer diaphragm accumulators or as spring piston accumulators. Such pressure accumulators are schematically depicted in FIGS. 1a, 1b, 1c and 1d, respectively. In the variants shown in FIGS. 1a to 1d the usable volume at 20.degree. C. is identical. As is apparent, the respective size varies considerably. In addition, problems exist in the case of gas-filled pressure accumulators with respect to the temperature dependency and the tightness over the endurance performance. In the case of gas multilayer diaphragm accumulators, further drawbacks are their considerable weight and high costs. In the case of spring piston accumulators the problem exists in the wear of the seal between the cylinder and the piston.